1、Standard Method of Test for Analysis of Structural Steel Coatings for Hindered Amine Light Stabilizer (HALS) AASHTO Designation: T 338-09 (2014)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4c T 338-1 AASHTO Sta
2、ndard Method of Test for Analysis of Structural Steel Coatings for Hindered Amine Light Stabilizer (HALS) AASHTO Designation: T 338-09 (2014)11. SCOPE 1.1. This method is designed to determine the presence of hindered amine light stabilizer (HALS) in the polyol portion of a two-component acrylic ure
3、thane coating. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practi
4、ces and determine the applicability of regulatory limitations prior to use. 2. APPARATUS AND MATERIALS 2.1. Gas chromatograph with mass spectrometer detector. 2.2. 5 percent phenyl methyl siloxane capillary column. 2.3. Reference HALS sample. 2.4. Hexane, HPLC grade. 2.5. Centrifuge. 3. INSTRUMENT C
5、ONDITIONS 3.1. Install and condition the column in the chromatograph in accordance with manufacturers recommendations. Establish operating conditions that yield acceptable separation of the components. See Table 1 as a guide for initial instrument conditions. Values may need to be altered to achieve
6、 necessary resolution of components. Allow sufficient time for the instrument to reach equilibrium and to produce a stable baseline. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c T 338-2 AASHTO T
7、able 1Initial Instrument Conditions Injection Port Mode Splitless Carrier gas Helium Initial temperature 250C Pressure 7.6 psi Total flow 54 mL/min Purge flow 50 mL/min Purge time 2 min Injection volume 1.0 L Column Parameters Nominal length 30 m Nominal diameter 0.25 mm Nominal film thickness 0.25
8、m Maximum temperature 325C Mode Constant flow Initial flow 1.0 mL/min Oven Parameters Initial temperature 50C Maximum temperature 325C Equilibration time 0.5 min Initial time 1.0 min Temperature ramp 1 25.0C/min to 250C Hold time 1 15.0 min Temperature ramp 2 50.0C/min to 300C Hold time 2 5.0 min Ma
9、ss Spectrometer Transfer line heater 280C Solvent delay 2.0 min 4. PROCEDURE 4.1. Prepare standards by adding reference HALS compounds to hexane to obtain the desired concentrations. Record the weights of hexane and reference HALS used to the nearest 0.1 mg. These standards will be used to obtain re
10、tention time data and atomic masses incidental to the specific HALS. 4.2. Prepare samples by thoroughly mixing two parts hexane to one part polyol in a centrifuge tube. (Note: 10.0 mL of hexane and 5.0 mL of polyol is a suitable working volume.) Record the weights of hexane and sample polyol used to
11、 the nearest 0.1 mg. Cap the centrifuge tube and centrifuge for 5 min at a minimum relative centrifugal force (RCF) of 43. See Section 5.1 for RCF equation. Fill a sample vial with the resulting supernatant. 2015 by the American Association of State Highway and Transportation Officials.All rights re
12、served. Duplication is a violation of applicable law.TS-4c T 338-3 AASHTO 4.3. Inject a 1.0-L aliquot of the appropriately prepared reference HALS standard. Determine the retention times for the associated peaks and the atomic masses of the reference HALS compounds. 4.4. Inject a 1.0-L aliquot of th
13、e prepared sample. Determine qualitative presence of the specific HALS by comparing retention times and verifying atomic masses of the HALS compounds. 5. CALCULATIONS 5.1. Calculation for Relative Centrifugal Force (RCF): RCF = 0.00001118 r N2(1) where: RCF = Relative Centrifugal Force, r = rotating
14、 radius (cm), and N = revolutions per min. 6. REPORT 6.1. Report qualitative results for the presence of the HALS compound. 6.2. Report quantitative results to the nearest 0.01 percent. 1Formerly AASHTO Provisional Standard TP 66. First published as a full standard in 2009. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
